Dynamometer



Juiy 24, 1923.

- lAlZf' G. H. WALKER DYNAMOMETER "Filed March 2a 1921 2 sheets-sheet 1 Figi.

INVENTQR @www5/54W* DYNAMOMETER Filed March 28. 1921 2 Sheets-Sheet 2 nNvENTUR v www,

Patented `l'uly 24, 1923.

E l i i GEORGE HENRY WALKER, OF WORCESTER, ENGLAND, ASSIGNOR T HEENAN &

FROUDE, LIMITED, 0F MANCHESTER AND WORCESTER, ENGLAND.

DYNAMOIVIETER.

Application led March 28, 1921. Serial No. 456,088.

To all whom t may concern:

Be it known that I, GEORGE HENRY WALKER, a British subject, residing at Worcester, county of Worcester, England,

have invented certain new and useful Imw provements in Dynamometers, of which the following is a specilication.

This invention relates to improvements in rotary absorption dynamometers of the well known Froude type.

In the specification of Harrisons prior U. S. Patent No. 1,035,700, there have been described means Jfor regulating the output of the dynamometer by means of automatically controlling the admission and discharge of water to and from the dynamome ter casing, in such a way that the output is proportionate to the quantity of weights which are suspended at the end of the balance arm. With such an arrangement the closing` of the output valve chokes water back into the dynamometer casing, and has the effect of increasing the power absorbed by the dynamometer with the consequence that the dynamometer casing tends to rotate on its trunnions, and to overcome the dead load of weights which are suspended at the end of the lever arm. Immediately the arm starts to rise above the horizontal, the rotation ofthe casing carries the outlet valve body with it, and the outlet valve is set to open when this occurs. The water passing out from the dynamometer casing then has an easier means of egress; the casing is partially emptied of water, and the amount of power absorbed by the dynamometer falls, with the result that the dead weights suspended at the end of the lever arm are immediately capable of depressing the arm, closing the outlet valve until `Finally the power absorbed by the brake is sufficient to cause the lever arm to float, while suspend ing the dead load of weights suspended at the end of it.

It will thus be evident that in order to vary the power absorbed by the dynamometer, itis necessary to add to, or reduce, the number of weights suspended at the end of the lever arm. When thedynamometer is in action absorbing power developed by any prime mover and the lever arm floating approximately horizontally, the act of adding a weight to the dead load already in place at the end of the arm has the natural effect of depressing the arm, and causing the outl let valve partially to close, as just explained. This causes the dynamometer to start absorbing more power until the additional weight has been balanced; the arm then continues to float in a new position which is slightly lower than the first. Similarly reduction in weight at the end of the arm will cause the outlet valve to open slightly, allowing the water to How more freely out of the dynamometer casing, and diminishing the power absorbed by the brake yuntil again it equals the torque represented by the weights suspended at the end ot' the lever arm. Hitherto it has not been found possible to apply this system ot control to reversible dynamometers fitted with two rotors, one for absorbing power ahead and one astern, owing to the fact that in changing the direction of rotation of the dynamometer, the ordinary outlet valve gear would have caused the valve to open instead of shut, and vice versa.

The present invention has for its object to arrange a system of valves and valve operating gear such that the output of the dynamometer, irrespective of the direction of rotation, is automatically proportioned to the amount of load, represented by weights acting upon an extension or arm of the dynamometer casing. p

The invention will be fully described with reference to the accompanying drawings.

Fig. 1. is an end elevation of two armed dynamometer with the brake bands of the valve operating gear in section.

Fig. 2, is a front elevation of two armed dynamometer.

Fig. 3. is a vertical section to an enlarged scale through controlling valve. a5

Fig. 4. is a longitudinal section of same.

Fig. 5. is a view to an enlarged scale of stop mechanism of the valve operating gear.

Fig. 6, is a diagrammatic view of the weighting arrangementof a one armed reversing dynamometer. y

The compartment of the dynamometer casing C which with its rotor absorbs power in a clockwise direction of rotation, is separated from the compartment which absorbs s power, in a counter-clockwise direction, by means ot' a partition between the two compartments which prevents water from circulating from one -compartment to the other.

The main inlet water pipe A is split up 310 into two'branches a, a', in each oir' which is inserted a valve B or B respectively by means of which the water may be allowed'- to flow ,cor may be prevented from flowing'- into the dynamometer casing, one valve B controls the flow ofl water into the one compartment, and the other valve B controls the iow of water into the other compartment of the dynamonieter casing'.

The main outlet pipe D is also connected to twob'ranc'h outlet pipes CZ and d connettedE respectively to the outlets from the two'compartinents of the casing and in each o'i"thefp'il'oescl` and d is'inserted a valve E E bywhic'h the' egress of the water from the compartments can be governed. The valve E controls' the water passing out of one compartinent and the valve E the water passing out ofr the other compartment.

The valves B B l E are' oi"l the saine cginst-iuc'tion as shown in YFigs. 3 and 4. -Each valve consists of a body F lined to tli'ellynaiiiomcter casing C so that when the casing rocks on its trunnions C" it carries tliebod'y of the valve with it in the same dire'ction. The central plug F of the valve is connected by `a seriesoic levers and links i'vitli `knuckle joints' (which will be described later) to an immovable part of the dynamo1neter' casing so Athaty when the valve body F is moved the plug F is caused to rotate through part ofa circle and therebyalt'er the position of the'lportsl f inthe plug relative tothev ports f2 in the cylindrical sleeve FF' carried in therbofd'yF thus altering the eiiective area of thelvalve opening.

Moreover the water entering the valve under pressure presses equally on diametrically opposite positions of the plug I4", so that the water pressure has no tendency to force the plug F so closely into engagement withl the body l` as to cause diiiculty in turningit.

The dynamometercasing is provided with ltwo lever arms G and G the arm G counterbalancing the resistance ot the dynamonr eter when running clockwise and the arm G counterbalancing the resistance when running anti-clockwise.

At one end of the shaft `C2 of the rotor is' fixed an operating gear K for controlling the outletvallves'E E', Theoperating gear consists' of a brake Hband 7c encircling the dynamometer shaft'v C?, the necessary Vgrip being obtained by means of springs la tending ,to'close the two halves ot the' brake` bandI so' that the rotation of the shaft C2 tends' toI carryvthe brakek band 7c with it. and to tthrow the links of the valve gear in a certain direction. lThis action continues untilfthe brake band chhas reached a certain position, when a projecting lever k2 hits against a stop 703' or a stop 7c4 iiXed to a stationary part of the dynaniometer supports or casing'. Thel lever sz in turn operates a.

cam h5 which separatesthe tavoh'alves oi the brake band against the action ot the spri-ngs, and removes the pressure of the brake band uponthe shaft. rThis is ra mechanical detail which avoids-excessive pressure, and consequently heat, being develo ped by the rubbing surfaces of the brake when the dynamometer is running continuously.

The operating outlet valve E of the near compartment (looking in the direction oi the arrow F ig. 2) by the link m, lever m, shaft' mi', screwed rod m3, lever mit, shaft m5, lever m, rod mi and' rod m8. Theconnections to the valve `E ofthe tar compartment are the saine to the rocking shaft m5 which is connected through the lever m9, rod m10 and rod will to the valve lt. The setting of the two valves is such that when the direction oft rotation is clockwise, the trip gear takes up a position (regulated by the position ot the stop) such that the outlet valve of one rotor compartment is partially closed, 4causing power to be absorbed in this compartment of the casing. The other outlet valve being controlled by the same system of levers and links is thrown into approximately a fully open position permitting water to flow easily away from the casing, and allowing the rotor in `this particular compartment to revolve idly.

The inlet valves B and B are controlled by an operating gear N of similar construction to the operating gear K and operated in the same manner. The operatingk gear il is connected to the inletv valve B of the far compartment (looking. in the` direction of the arrow Fig. 2),- through the link n, link n', shaft a2, lever a3 rod n* and screwed rod 715. The inlet valve ofthe near compartmentl is connected to the trip gear N through the link n, link n', shaftm, lever a, rod fri? and screwedrod ne. y i

The two inlet valves B B are used only as distributors and not as regulators of the quantity of water supplied. They are always fully open, or fully closed, according to the position of the operating gear working under the influence ofthe rotation of the shaft, so that the rotor compartment in which power is being absorbed receivesa full supply of water through the inlet valve which is open, while the idle compartment is starved of water.

When the direction of rotation of the dynamometer is counter-clockwise, the balance weights which control the amount of powerabsorbed are suspended upon the` right hand lever arm G (Fig. l). When the direction of rotation is clockwise, these weights are suspended on the left hand lever arm G.

In dynamometers of large size, the number of balance weights which have to be snsile pended at the end of the long arm in order to counterbalance the resistance of the dynamometer to rotation becomes unwieldy, and the weighing device shown in Fig. 14C may then be adopted. At 'the end of the dynamometer arm G is mounted a vertical link g connected to a horizontal lever g pivoted on a fixed fulcrum g2. At one end of the lever g balance weights w or w are suspended according to the direction of rotation of the dynamometer. A sliding weight 'L02 moving over a scalesis alsoprovided on the lever g.

What I claim as my invention and desire to protect by Letters atent is 1. A rotary reversing absorption dynamonieter of the type referred to comprising in combination a casing divided into compartments, a load arm extending therefrom, a rotor arranged in the casing, a shaft car` rying the rotor, inlet and outlet pipes from the compartments, valves arranged in said pipes, operating gears mounted on the shaft carrying the rotor and links and levers connecting the operating gears to the valves.

2. A rotary reversing absorption dynamometer of the type referred to comprising in combination a casing divided into compartments, a rotor arranged in the casing, a shaft carrying the rotor, inlet and outlet pipes from the compartments, valves arranged in the outlet pipes, an operating gear mounted on the shaft carrying the rotor and links and levers connecting the operating gear to the valves to operate the latter.

3. A rotary reversing absorption dyna mometer of the type referred to comprising in combination a casing divided into compartments, a rotor arranged in the casing, a shaft carrying the rotor, inlet and outlet pipes from the compartments, valves arranged in the inlet pipes, an operating gear mounted on the shaft carrying the rotor and links and levers connecting the operating gear to the valves to operate the latter.

1. A rotary reversing absorption dynamometer of the type referred to comprising in combination a casing divided into compartments, a rotor arranged in the casing, a shaft carrying the rotor, inlet and outlet pipes from the compartments, valves arranged in said pipes, brake bands surrounding the shaft carrying the rotor, two springs controlling the brake bands, stops to limit the movements of the band and links and levers connecting the brake bands to the valves to operate the latter.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses this 11th day of March, 1921.

GEORGE HENRY WALKER. Witnesses:

Lrzzm RANKINE, WILLIAM HOWARD. 

